The present invention relates to an image forming apparatus for obtaining picture in an electrophotographic way that a toner image is formed on an image carrier and is transferred onto transfer material. More particularly, it relates to an image forming apparatus for use as a printer, a copying machine, a facsimile machine, or similar machines having a demountable process cartridge provided therein in which the image carrier is integrated with at least one of a developing arrangement and a cleaning arrangement.
Image forming apparatuses, such as printers and copying machines, have advanced to provide more automated functions, component density complications have increased; these higher densities are needed to provide a lighter weight and have higher operating functions.
The image forming apparatuses of transfer type have been substantially improved in its transfer material feeding performance. However, the apparatuses heretofore used have the disadvantage that they cannot be made free of jamming yet. In order to remove the jamming transfer material (hereinafter referred to as the jamming paper), an operator has to open outside doors of the apparatus, and move all of or parts of moving arrangements for feeding the transfer material to make working rooms inside the complicated apparatus so that the operator's hand can reach the jamming paper. Manufacturers have to take in consideration that clearing of the jamming paper can be made easily and readily as it is ordinarily made by the operator having no special skills.
As a typical example of the apparatus for which such a consideration is taken, there have been proposed apparatuses of shutlex type and clamshell type (for example, the Japanese Patent Laid-Open Publication No. 279870/1986). In such apparatuses, a variety of elaborations were made to widen the working area and simplify necessary manipulations, for example, casings could be opened itself to partition a sheet feed route, grips of movable sections in the sheet feed route of the transfer material were colored so that the operator could recognize them easily, a jamming position was indicated on a display, or parts of a transfer arrangement, a sheet feed arrangement, and similar image forming arrangements were assembled as independent units so that any of them could be isolated to clear the sheet feed route.
However, the apparatuses mentioned above have the disadvantage that the operator himself has to move the movable sections to clear the sheet feed route of the transfer material, thereby making the working room. This is troublesome work. The working room obtained for clearing of jamming is too narrow to easily insert a hand into it to remove the jamming paper. To release the sheet feed route, he or she had to search for a position where the jamming paper is. If the sheet feed route is complicated, particularly in a color both-side, high speed, high performance image forming apparatus, he or she had to move a plurality of movable portions at a time to release a plurality of sheet feed routes. He or she was not only confused in shooting the jamming position for a long time, but also might be involved in erroneous manipulations, resulting in some troubles.
The conventional image forming apparatuses have the disadvantage in the workability that as they were ordinarily leveled at around a waste of the operator, he or she had to sit down on his or her kneels or bend his or her body not only to see, but also to clear of the jamming paper.
In any way, as the conventional apparatuses caused the operator himself or herself to move the movable sections to release the sheet feed route, they were not only disadvantageous in the workability, but also might injure him or her or the image carrier if his or her hand had to force or put into narrow spaces.
In order to replace the process cartridge or cassette of the conventional apparatuses, the operator had to pull it out of the apparatus body to a great extent. This work was not only very troublesome, but also needed for him or her to have a mighty force to bring up the heavy process cartridge or cassette which might be in contact with the sheet feed roller or to erroneously drop it down.
In short, the conventional apparatuses are disadvantageous in the simplicity of work and safety when the jamming paper is to be removed or the process cartridge or cassette has to be replaced.
In view of the foregoing, it is a general object of the present invention to provide an improved image forming apparatus which provides wider working space for clearing of jamming paper, allows an operator to easily replace a process cartridge or cartridge, and is superior in the maintainability. More specifically, it is an object of the present invention to provide an improved image forming apparatus for color images having a heavy process cartridge which can be cleared of jamming paper or replaced safely and easily.